No cash dispensed from ATM

Today, 05th November, 2018 I tried to withdraw money from an FNB ATM situated in Dean Road, Newlands, Cape Town. I received the notification on my mobile app that the withdrawal was successful however no cash or receipt came out and the ATM simply went to a blank white screen. I called the lost card number to try to get this resolved only to be told I had to go into a branch. So I went to the branch in Claremont, Cape Town and was informed there that the dispute can take up to 72 hours. This is simply unacceptable in this highly technological era. We are in 2018, surely the ATMS report to a central point so say yes they are online or not??? It certainly does connect to some central server otherwise how would it know which account to transact against??? I demand my funds back immediately, as I did not receive them and I don't see why I should wait for a something that is an FNB fault. Come on this is 2018!!!!!! Get with the future FNB!!!!